Yep i was exactly in your situation, mine wasnt completely coming off, just the back part, so i just used a 3M tape and now she holds pretty strong, after 5 months, zero trouble. If yours coming off badly, just take the whole thing and re-apply new 3M tape
__________________ 07 Mustang Pony pkg 4.0L V6
Appearance: Roush hood scoop, rocker panel, custom GT500 chin spoiler, side louvers, racing stripes, shifter bezel, door sill plates, Sequential tail lights
Performance: C&L intake, Bama/Tillman 91 Race tune, SCT X3, Mac dual exhaust kit, OEM Ford 3.73 gears/T-lock on 7.5' | 
Any one else have trouble with roush rear louvers mounting 
